The present invention relates an image detecting apparatus used to detect a pattern of lines on a palm of a hand which may be used in a security system, for example, to determine whether a person should be given access to a secure area.
A human palm has three main lines, known as the Head line, Heart Line and Life Line in palmistry. The patterns of lines on the palm, including these three lines, are unique for each person, and therefore, the patterns formed by these lines can be used as a basis for identifying different people.
Conventional palm line or palm line pattern reading devices are known, as described in U.S. Pat. No. 4,032,889, and utilize a mechanical scanning system in which a group of mechanical line sensors scan the surface of the palm in order to detect the lines of the palm. However, the mechanical scanning system cannot read the palm lines or patterns quickly since the surface of the palm is a complicated shape. Further, the size of the mechanical line sensors and the distance between the mechanical line sensors result in the scanning system having a low resolution, thereby reducing the accuracy of the palm line pattern that is detected.
Another method for detecting a palm line pattern that has been proposed uses an optical scanning system. In this system, the palm is placed on a flat glass surface similar to a document glass of a plain-paper copying machine in order to scan the palm. However, this system is unable to read the entire area of the palm due to insufficient contact between the glass surface and the palm. Therefore, portions of the lines which do not contact the glass may not be read or will have a low contrast, thereby reducing the accuracy of the image of the scanned palm.